It’s an accepted fact that there is a tendency for certain natural disasters to occur at specific times of the year. We have a definite hurricane season, parts of the country have fire seasons, and tornados tend to pop up during predictable times. But could this be true for earthquakes?
Possibly. A study conducted in Taiwan, published April 14, 2021 in the journal Science Advances, claims to have discovered a link between the island’s seasonal rainfall cycle and earthquakes. Specifically, Taiwan has a rainy season from about May to September, then a much-drier period during October through April. The study documented how large earthquakes seem to occur more often during the dry season.
The connection could be the groundwater. Having such large variations in rainfall in a year can dramatically affect groundwater levels. Perhaps empty subterranean cavities when the water table recedes can trigger an earthquake?
Several hundred years of earthquake and rainfall data, plus satellite data related to water storage, supports that theory: earthquake activity was highest during the driest period (February, March and April), and the quietest earthquake period matched the wettest months (July, August and September). This suggests less groundwater weighing down the land lets the terrain rise, thus increasing the chances of earthquakes.
Of course, nothing is simple. The correlation was stronger on the western side of Taiwan than the eastern side, suggesting a more complex pattern. And not all earthquake-prone areas have well-defined wet and dry seasons. Still, It’s an interesting idea that warrants more research.
For the complete story, read “Is There Such a Thing as Earthquake Season?”, posted by Kelly Kizer Whitt at https://earthsky.org/earth/earthquake-season-taiwan-dry-monsoon?.